No. 3, October, 1921] GENETICS 205 



parasitism of Chaetocladium was related to the sexual process and had arisen as an attempt 

 at hybridization. New data in support of this view are furnished by the Alueor parasite 

 Parasitella simplex, of which the author has isolated the (+) and (-) races and obtained 

 the zygospores. The formation of the gall cell is essentially similar to the process in Chae- 

 tocladium, except that in Parasitella the gall cell formed by a mixture of protoplasm of parasite 

 and host becomes a storage organ in the form of a thick-walled body resembling an azygospore. 

 Both (-I-) and (-) races of Parasitella parasitize both (+) and (-) races of most Mucor species, 

 such as Rhizopus nigricans, Mucor Mucedo, and M. heimalis. Parasitella (+), however, 

 parasitizes only the (-) race of Absidia glauca, and Parasitella (-) only the (+) race of this 

 Absidia. A (-) race of Chaetocladium parasitizes only the (+) race of the same Absidia 

 while parasitizing both (+) and (-) races of Rhizopus and Mucor. It is concluded that the 

 hypothetical sexual substance which distinguishes the (+) and (-) mycelia of Absidia is in 

 this case identical with the substance which induces parasitism; and that the parasitism of 

 Chaetocladium and Parasitella is sex-limited in respect to Absidia glauca, but is not sex-limited 

 in respect to Rhizopus and other genera. From the foregoing and from the fact that the (+) 

 and (-) races of Rhizopus show imperfect hybridization reactions with the opposite sexes of 

 Absidia it is further concluded that Rhizopus and Absidia possess like sexual complements 

 but that iEWzopMS has a special complement in addition which completes the sexual and para- 

 sitic complements of Parasitella (+) and Parasitella (-) and brings them into activity. — 

 A. F. Blakeslee. 



1310. Castle, W. E. A new type of inheritance. [Rev. of: Schmidt, Johs. Racial 

 investigations. IV. The genetic behavior of a secondary sexual character. Compt. Rend. 

 Trav. Carlsberg Lab. W: 1-21. Color pi. 1-5. 1920.] Science 53: 339-342. 1921. 



1311. Chevalier, A. Sur I'origine des pommiers ^ cidre cultiv(5s en Normandie et en 

 Bretagne. '[On the origin of cider apples cultivated in Normandy and Brittany.] Compt. 

 Rend. Acad. Sci. Paris 171 : 521-523. 1920. — For northwest France there have been described 

 500 to 1000 varieties of cider apples. The origin of these apples is not well known. It wag 

 formerly held that there was but a single Linnaean species, Mains communis, which included 

 all cultivated crabs and apples, but excluded the Malus of eastern Asia and North America, 

 which are very different species. — It appears necessary to divide Malus communis into 4 ele- 

 mentary species, capable of hybridizing among themselves and producing many fertile races 

 which are sources of cultivated varieties. These species are Malus acerba Merat, M. dasy- 

 phylla Borkh., M. praecox Borkh. (these 2 are often united as M. pumila Mill.), and M. pruni' 

 folia. — The species M. acerba Merat (1815) includes apples growing spontaneously in the forests 

 of nearly all of Europe. It had previously been designated under the name M. spinosa Rous- 

 sel, Fl. Calvados (1806) and as M. sylvesiris. Miller Gard. Diet. (1759). It is this last and 

 oldest name that should be preserved. — All French authors have erroneously assigned the 

 origin of cider apples to M. acerba and of table apples to M. dasyphylla. Examination of many 

 varieties of cider apples, cultivated in the west, proves that none of them agreed with M. 

 acerba, but they should be referred, like the varieties of our gardens, to M. dasyphylla, a species 

 introduced from Spain. The explorer G. Capus discovered M. dasyphylla, occurring spon- 

 taneous in forests in Armenia and Turkestan, in 1881. Its culture extended from remote 

 antiquity throughout the borders of the Mediterranean Basin and to-day it is found subspon- 

 taneous in forests of Sicily and of Spain. The author observed it under similar conditions 

 in the department of Alpes-Maritimes approaching an altitude of 3000 feet. — This species, 

 represented in its native home by many races {M. ynitis, M. astracanica, M. N eidzwetzkayana, 

 etc.) has been the point of departure of edible varieties cultivated in Egypt under the 19th 

 dynasty (Joret). — M. praecox is only another paradise or Saint-Jean apple used as a stock 

 for dwarfing garden varieties. It came originally from the southeast in Russia and Asia 

 Minor and appears to have been carried to Europe at the time of the Crusades. M. pruni- 

 folia originated in central Asia and its culture has spread on the one hand towards Russia 

 and Siberia and on the other towards China and Japan. — The 4 species cited and their 

 diverse races, still not well known, transformed by culture and by hybridizing among them- 

 selves in various degrees, have supplied the very numerous kinds of cultivated apples. 

 [See also Bot. Absts. 8, Entry 377; 9, Entry 1288.]— C. S. Crandall. 



BOTANICU. ABSTRACTS, VOL. IX, NO. 3 



